二连盆地巴音都兰凹陷油气成藏条件研究

Research on Petroleum Geological Conditions of Bayindulan Sag of Erlian Basin

巴音都兰凹陷是二连盆地重要油气勘探区之一,具有良好的油气成藏条件。综合分析其油源、生储盖组合及圈闭等条件,表明:巴音都兰凹陷烃源岩发育,有机质丰度高,属于Ⅱ1和Ⅱ2型干酪根,但有机质热演化程度较低;生储盖组合条件良好,北洼的腾一段、腾二段,南洼的阿尔善组顶部、腾一段和腾二段均发育良好储层,以扇三角洲砂体为主。阿尔善组顶部及腾一段底部发育较深湖相泥岩盖层,形成多套良好生储盖组合;主要发育背斜和断层等构造圈闭油藏,也有岩性圈闭、地层圈闭和复合圈闭油藏,圈闭形成期早,与油气生成和运移期配置关系好,具有良好的聚集和保存条件。分别总结了北部洼陷和南部洼陷的成藏特点,建立了成藏模式。

Bayindulan Sag was one of the important oil and gas exploration areas of Erlian Basin, it hadgood conditions for hydrocarbon accumulation. The conditions of integrated oil sources, source -reservoir-cap combination and traps were studied. The result shows that hydrocarbon source rocks are development in Bayindulan Sag, it belongs to Ⅱ1 and Ⅱ2-type kerogen,organic matter abundance with low level of thermal evolution of organic matter. Source-reservoir-cap combination is good, reservoirs in the members of Teng1,Teng2 of North Trough, at the top of the Arxan, Teng1,Teng2 of South Trough are well-developed to the main fan-delta sand body; on the top of Arxan and bottom of member of Teng1 developed deeper lacustrine facies mudstone caprock, the formation of several good source -reservoir-cap combination. The main development of structural trap hydrocarbon reservoirs, such as anticlines and fault traps, but also lithology, stratigraphy and complex, trap reservoirs, at the early stage of traps, it has a good relationship with gas generation and migration in configuration, and good conditions for the accumulation and preservation. Characteristics of reservoir formation in northern and southern sag are summed up respectively, a model for reservoir formation is established.